Misfire at 4000RPM
I just acquired an 89 probe (non turbo) 5 speed with almost 200,000 miles on it. It was my mother's, garaged, never driven over 55, and always serviced well. It runs perfectly after a tune up and oil change but misfires at exactly 4000rpm in every gear (I don't think the car ever saw 4000RPMs before). When I hit 4000, the tach drops instantly to 0 and the car slows noticeably. If I let off the gas a bit, the tach jumps right back up to about 3800 or if I shift, it's fine.
Anybody got any ideas?